Carl hoepfner



(No Model.)

' C. HOEPFNER.

BLEGTROLYTIG PRODUCTION OF METALS.

No. 507,130. Pat ented 001;. 24, 1-893.

'YRjUNITE D Y STATES PA ENT ..of. philosophy and chemist, a subject of the- .CARL HOEPFNER, OF BERLIN, GERMANY.

ELECTRClLYTIC PRODUCTION OF METALS.

SPECIFICATION forming part'of Letters Patent No. 507,130, dated October 24, 1893. a

' Application filed Jul 16,1888. Serial ire-280,091. on specimens.) Patented-in England April 23, 1885, No. 6,736, and in v 7 Germany March 2.1888,No.63.'782.

;To all whom it may concern:

Be it kuownjhat I, CARL I-IOEPFNER, doctor .:King of Prussia and German Emperor, resid- German Empire, have invented certain new ing at Berlin, in the Kingdom of Prussia and and useful Improvements in the Electrolytic Production of Metals, (for which patents have been obtained in Great Britain, No. 6,736,

vdated April 23, 1885, and in Germany, No.

.. 7 53,782, dated March 2', 1888;) andl do hereby declare the following to be a full, clear, and exact description of the invention, such as will enable others skilled in the art to which it appertains to make and use the same.

I The invention relates to the extraction of metals from their ores, or troni matte, or other materials, and is designed more especially for ,the extraction of copper or copper and silver free fromoiher metals allied thereto and usually found in cupriferous and argentiferous ores or pyrites.

The invention has for its object the provisv.ion of a simple and economical mode of extracting these metals, and it consists in the method or process of extracting the metals refer-red to, as will nowbe fully described. In carrying out my inventionl'proceed as follows: I first form a solution of cupric chloride (GuOl by means of a solvent of cuprous chloride and chloride of silver, as for instance,

.by dissolving the cupric chloride in a sat-u- .Tfitfld solution of chloride of sodium, calcium,

or magnesium. The ore, matte or pyritesare reduced preferably to a pulverulent condition and are then leached out with the cupric chloride solution, whereby the latterriscon- "vertedinto a cnprous chloride solution. Such metals as; coppea silver', lead, the, especially when presentin the materialftreatedinthe "form of, sulphides, are readilv dissolved by thecnpi ic chloride solution and-the latteris converted into a cuprou's chloride solution according to the following equations;

or H v v 2-CuGl,-}Ag;S=S+CL1,,(3l l- AgCi. Should the material treatedcontaiu copper in the form -ot'an oxide, a suflicient quantity of acid or other solvent is added to the cnprous chloride solution, care being had that the whole of the cupric chloride present is first converted into cuprous chloride. If the euprous chloride solutipn thusobtained contains copper only, or copper and silver, the latter may be eliminated by-precipitat-ion, either by means of metallic copper or by means of sulphide of copper, introduced into the cuprous chloride solution which is kept agitated so as to bring the whole of the solution in contact with the precipitant, the silver being obtained in a metallic form if metallic copper is used,

or in the form of a sulphide if sulphide of copper is used as a precipitant, a quantity of copper equal to that of the silver precipitated being dissolved and taking the place of the silver in the cnprous chloride solution. The silver may, however, be extracted from the cuprous chloride solution, and hereinafter called the electrolyte, simultaneously with the copper by electrolysis. To this end the elec trolyle is rapidly passed through series of anode and cathode cells of an electrolytic apparatus hereinafter called the electrolyzer, whereby silver only will be deposited at the cathodes first brought into contact with the electrolyte, while the copper will be deposited at the succeeding cathodes, these metals being depositedin the order of their position in the electrolytic series. In this electrolytic separation of the copper and silver the electrolyte is supplied to the anode and cathode cells in two separate streams, the cells of unlike name being separated from each other by a diaphragm impermeable tothe electrolyte but atfoixlin g f ree passage to the electric current. As stated the metals, silverand copper,will be de positedat thecathodcs, while the electrolyte at the anodesswill beconverted by the chlorine liberated, fromacuprous to a cupric chloride solution, which is afterward mixed with thesolution flowing from the cathodes for use as 'l hc chlorine liberated at the anode acts in szoZ-u jrqsceiuli, resulting in'the generatiouot elcctro-motivo force thatis not only favorable to but assists in the separation or extraction of the metals an 1 the conversion of the electrolytc.

Inasmuch as the electrolyte obtained in the manner set forth from materials such as de; scribed almost invariably contains, besides copper and silver. other metals usually assoc'ated with the latter, such as iron, lead, arsenic, antimony, bismuth, cobalt, 850., these may be obtained with the copper, or the cop per and silver in the form of alloys by electrolysis, or in a mom or less pure state by passing the electrolyte, as described in refer ence to the electrolytic separation of silver from copper, rapidlyth rough aseries of anode and cathode cells, the metals being deposited at the cathodes in the orderof their position in the electrolytic series. Iprefcr, however, to free the electrolyte from these metals in order to obtain metallic copper or copper and silver in a pure state,and this may be efiected by any suitable precipitant, as for instance carbonate of lime, the proportion of the precipitant depending upon the proportion of undesirable metals contained in the electrolyte, which is determined by analysis. The separation or precipitation of the undesirable metals by means of carbonate of lime is readily effected for the reason that said metals will be acted upon by the lime before the copper and silver, and for the further reason that the quantity of lime used is proportionate to that of said undesirable metals, thus leaving the copper or the copper and silver in the solution unaffected.

Of course any solution containing copper or copper and silver and other metals such asreferred to, may be treated with carbonate of lime, but this treatment is more especially applicable to solutions of cuprous chloride.

Inasmuch as cupriferons ores contain more or less iron which may enter into solution in the preparation of the electrolyte, the repeated use of the regenerated cupric chloride solution would'result in an accumulation of an excess of iron, which is undesirable. This is also avoided by treatment of the electrolyte with carbonate of lime. The removal of the iron may also be elfected by injecting air or oxygen into the electrolyte, which results in the formation of oxychloride of copper that acts as a precipitant for the oxide of iron, but a small quantity of copper, comparatively speaking, being necessary. This reaction takes place according to the following equation:

This tendency of the cuprous chloride .to oxi- I The acidnla'lion may be clfected by the addition in the presence of air, ofsulphu rous acid,

to the solution of cnpric chloride.

Instead of carbonate of lime, caustic alkalies or alkaline earths or their carbonates or to the precipitant used in the form of oxides, or in the form of arsenate and antimonate of iron or copper, the arsenic and antimony being present in the solution in the form of arsenio'us and antimonious acids, or arsenic and antimonic acids which are converted by the precipitant into insoluble arsenic and antimonic salts; while it an oxide or carbonate of copper is used the arsenic and antimony are converted into insoluble arsenate or'arsenite of copper and the corresponding salts of antimony. Inasmuch as the electrolyte contains copper it may readily happen that the salts last referred to will be formed without the use of a. copper salt when lime or an al- 'kali is used as. a precipitant. In either case but a comparatively small proportion of cop per goes over with the precipitant, which quantity is in no case greater than the quantity of the arsenic and antimonic salts precipitated, so that but an unapnreciable quan-' tity of copper is lost.

That the undesirable metals referred to may be efiectu'ally eliminated from the electrolyte in the manner described and before the electrolyte is subjected to the action of the electric current without affecting either the copper 'or the silver, whenever the latter is present in the solution treated, has been fully demonstrated by practice on a la ge scale, care being bad to regulate the quantity or proportion of the precipitant according to the-quantity or proportion of such undesirable mctals present in the electrolyte, so that a solution containing copper or copper and silver only, is obtained as an electrolyte from which the silver may be separated in a substantially pure form by electrolysis in the manner above set forth, or said silver may be removed'from the electrolyte by precipitation as described, before the electrolyte is subjected to electrolysis. The described process possesses many ad vantages, some of which are of great importance' Thus, for instance, copper from low grade copper ores, or'matte, or other cupriferous materialspoor in copper can be readily and rem nneratively obtained in asimple manner. On the other hand, a saving in electrical energy is also effected, since one amper'e will deposit or precipitate twice as much copper from a cuprous as from a cupric solution, and when such cuprous solution is previously freed from the salts of objectionable metals as described, pure copper will be the result.

. When cupriferous ores containing silver, or argentitcrous ores are treated according to my process, the silver can be extracted or separated at a comparatively small expense, while in the case of rebellious'argeutiferous ores the usual expensive chloridizing roastiug is dispensed with,as well as the losses in quicksilver or sulphate of copper in the subsequent amalgamation ofv the roasted ores,

which losses render the process of amalgamation so costly.

Any suitable apparatus may be employed in carrying out my invention, such. apparatus being shown in the accompanying drawings, in which- Fi ure 1 is a sectional elevation, more or less diagrammatic, of such an apparatus, and Fig. 2 is a longitudinal vertical section, and Fig. 3 a top plan view of the electrolyze'r.v

A indicates the reservoir for the cupric chloride solutions, which reservoir is connoctod with the leaching vat, B, by pipe, at, said'vat containing, the cupriferous or argentifcrous material to be leached. The leaching vat, B,is connected with a settling tank, 0, by pipe, I), and said tank is connected with the first pair of cells of unlike name of the electrolyzer D, through the branched pipe. 0. A similar branched pipe, d, conducts the eupricchloride solution from the last of the anode cells, and the solution free from metals from the last of the cathode cells of the series into a reservoir, E, where the two liquids commingle and are pumped byapump, 6, through pipe, f,into a collecting tank, F, from whence the liquid is conducted through pipe, g, back to reservoir, A

As shown in Fig.3, the electrolyte passes from tank, C, through pipe, c, and its two branches, 0, 0", into the first pair of anode and cathode cells of the electrolyzer, I), said cells being separated from each other by diaphragms, D, that are impermeable to the electrolyte but not to the electric current, said diaphragms being secured to posts, e', while the cathode cells are separated by partitions D extending from the opposite inclosing walls, h, of the electrolyzer towardthe end walls of the diaphragms, D. It will be seen that the electrolyte flowing into the first anode cell, 1, through branch, c, of pipe, c, passes around the two adjacent cathode cells, 1*, 2, into anode cell, 2, in an opposite direction, thence through the adjacent anode cell, 3, and so on through the remaining anode cells, 3, 4, 5, &C., to the last cell, 9, oi the series,

and thcncethrough branch, d, of pipe, at,

into the reservoir, E, that portion of the electrolyte pursuing a zigzag course through the elcctrolyzer. The same is the case with that portion of the electrolyte supplied to the cathode cells through branch, 0', of pipe, 0, the electrolyte flowing into the first cathode cell, 1, thence around the partition, D through cathode cell, 2, and so on to the last of the cathode cells, 9, oi the series, and thencethrough branch, 1", of pipe, 65, into reservoir, E, the anodes, A, and cathodes, 7c,

of the clectrolyzer being made of carbon and sheet copper respectively.

I have hereinbefore stated that. the din-- nhragms I) should be made of a material impermeable to the electrolyte but not to the electric current, and I prefer to employ diaphragms made of parchment paper reinforced leather, veneer, gelatine, asbestus, or'the like,

as described in my application for Letters Patent ot' the United States, Serial No. 378,616,

filed January 21, 1,891.

In the described elect-rolyzer cells of name are connected upin series in a manner well understood in the art, and Ihave deemed it unnecessary to illustrate or describe in do tail'the'electrical connections. t

Having thus described my invention, what I claim as new'therein, and desire to secure 1 1. The herein described process of obtaining by Letters Patent, is-

copper, which consists in first'torming a cu-' .prous chlorid solution such as described .by

leachinga cupriferous material with a cupric chlorid solution containing a solvent for cuprous chlorid, electrolyzing the cuprous chlorid solution so obtained and preventing the solution at the anode from comminglingwith the solution' at the cathode, whereby the cuprous chlorid at the anodeis reeonverted into eupric chlorid, substantially as set forth.

2. The herein described process of obtaining copper, which consists in first forming a euprous ohlorid solution by leaching acupriferous material with a cupric chlorid solution containing a solvent for cuprous chlorid: electrolyzing the cuprous chlorid solution so ob 'tained, preventing the solution about the anode from commingling with the solution about the cathode, and mixing together the electrolytic solutions after having been acted upon by the electric current for the purpose specified, whereby the ouprous chlorid at the anode is reconverted into cupric chlorid, substantially as set forth.

3. The herein-described process of obtaining copper and silver free from other metals, which consists in first forming a cuprous chlorid solution of these metals by leaching a cupriferous and argentiferous material with a cupric chlorid solution containing a sol vent for cuprous chlorid, separating from the cuprous chlorid solution so obtained such metals as iron, arsenic, antimony, cobalt, &c., then extracting the silver by precipitation, and lastly electrolyzing the cuprous chlorid solution, and preventing the saint-ion at the anode from commingling with the solution at the cathode for the purpose specified, whereby the cnprous chlorid at the anodes is reconverted into cupric chlorid, substantially as set forth.

4. The herein described process of obtain ing copper and silver free from other metals, which consists in first forming a cuprous chlorid solution of these metals byleaching a cupriterons and argentiterous material with a cupric chlorid solution containinga solvent for cuprous chlorid, separating from the cnprous chlorid solution so obtained such metals as iron, arsenic, antimony, cobalt, the, then extracting the silver by precipitation, and lastly electrolyzingthe cuprous chlorid solution, and preventing the solution at the anode too ing copper, which consists in first forming a cuprous ohlorid solution by leaching a capriferous material with a cupric chlorid solution containing asolvent for cuprous ehlorid, electrolyzing the cuprous chlorid solution so obtamed,preventing the solution about the anode from commingling with the solution about the cathode, mixing together the electrolytic solutions afterhaving been acted upon by the electriccurrent,and preventing an accumulation of iron therein by oxidizing and removing the latter, substantially as and for Y the purpose set forth. 6. The herein described process of obtainmg copper and silver free from other metals,

which consists in forming a cuprons chlorid solution of these metals by leaching a cnprifl erous and argentiferous material with a eupric chlorid solution containing a solvent for cnprons chlorid as described, separating from the cuprous chlorid solution so obtained such metals as arsenic, antimony, cobalt, &c., extraction the silver by precipitation, electrolyzing the cupro'us chlorid solution, preventingthc solution at the anode from commingling'with the solution at the cathode, mixing together thetwo solutions after having been acted upon by the electric current and pre venting an accumulation of iron therein by oxidizing and removing the latter, substantially as and for the purpose set forth.

Iutestimony whereof I affix my signature in presence of two witnesses.

CARL HOEPFNER.

Witnesses:

MARC M. ROTTEN, B. R01"; 

